Turbocharged and/or supercharged engine systems typically include a compressor and an air cooler upstream of one or more combustion chambers of an engine. Often, the combustion air comprises a mixture of ambient air and recirculated exhaust gas in an attempt to reduce undesirable emissions produced during combustion. Recirculated exhaust gas often includes considerable amounts of water vapor and, in relatively cold environments, the temperature of the combustion air may be lowered below the dew point of the combustion air resulting in condensation developing within one or more locations of the engine system, e.g., within components and/or conduits. Condensation may combine with acidic substances within the recirculated exhaust gas, e.g., sulfuric or nitric substances, to form aqueous acids which are typically more corrosive to engine components, especially metal surfaces, than gaseous acids. Additionally, condensation may form water droplets suspended within the combustion air which may impinge one or more surfaces of engine components. As such, the existence of condensation within the engine system may reduce engine system component cycle life, cause premature engine system component failure, and/or undesirably affect engine system performance.
U.S. Pat. No. 6,725,848 (“the '848 patent”) issued to Ramamurthy et al. discloses a method of controlling exhaust gas recirculation system based upon humidity. The method of the '848 patent includes sensing a humidity of combustion air within an inlet manifold, of combustion air downstream of a combustion air mixer and upstream of an inlet manifold, or of ambient air. The sensed humidity of the combustion air upstream of the inlet manifold or of the ambient air is correlated with engine speed, engine load, ambient temperature, intake manifold pressure, air/fuel ratio, and the flow rate of recirculated exhaust gas to determine the dew point of the combustion air within the manifold. The method of the '848 patent includes ceasing to recirculate exhaust gas if the sensed humidity within the inlet manifold, as sensed, approaches 100% or if a sensed temperature of the combustion air within the inlet manifold, as correlated, is less than a dew point for the combustion air.
Although the method of the '848 patent may determine if condensation is likely to occur within the inlet manifold as a function of the sensed humidity and may control recirculated exhaust gas as a function thereof, it requires sensing a humidity associated with the exhaust gas recirculation system. Additionally, the apparatus associated with the method of the '848 patent may require a humidity sensor exposed to the combustion air which may potentially decrease the integrity of the inlet manifold or of another component of the exhaust gas recirculation system. Furthermore, the method of the '848 patent only determines the likelihood of condensation within the inlet manifold which may not sufficiently monitor condensation with respect to additional engine system components.
The present disclosure is directed to overcoming one or more of the shortcomings set forth above.